Voice over IP (VoIP) is a the main standardized technology for voice communications over Internet and over private IP-networks such as most big modern telecom companies run today. In modern societies most of all telephone traffic is provided on this way. The most known exception from the rules is Skype, that doesn't use IP directly. The big advantage for Skype is that older type of routers and firewalls don't obstruct communication. The VoIP-technology supports also other multimedia techniques as video. The technology is also referred as IP telephony, Internet telephony, broadband telephony etc. Everybody who has internet can use this technology for free. You only need to have a SIP address, that looks remotely like an email address, but isn't.

SIP address are generally supplied for free, for example at LinPhone, or VoipBuster. After registration you get an email like address like mine carlo.vogels@sip.linphone.org or carlo.vogels@sip.voipbuster.com and password.

To receive calls you of course need a phone, and you definitely have one or more. You can use

  1. a classical phone (POTS) that you connect to VoIP Gateway on router (if it has one).
  2. a special VoIP phone that is connected to your router (the same way as an PC).
  3. a USB phone connected to a PC.
  4. or a softphone which is not a phone but a a piece of software running on your Iphone, Android or Windows.

Most likely you want to use your mobile phone. So you have to download a softphone-app from your Appstore. I recommend to download the open source LinPhone. After download you need to fill in your user ID (first part of your SIP), password, and provider (last part of your SIP). And READY! Now people can call you by using your SIP address. If some problems, than generally there is something with a router that has to be changed. A very few mobile providers unfortunately block VoIP, but this is seldom.

BUT not much people are using SIP addresses to call, so they will not understand you if you tell your new SIP address. People are familar with a "telephone number", for the expert known as a DID number. So the next step is to get such a DID number and forward it to your SIP address. Of course you need to choose a telephone number that is not expensive to call for your friends, family or clients, this will for most people their regional number. You can even add more numbers if you want if you have friends or clients in different regions of the country or world. Also you can say your current expensive telecom provider goodbye, and use your current number for VoiP. I'm using for this provider for my Dutch landline. You can compare more prices on this website. For example this Ukraine Mobile number will cost your 1.6 euro/month.

You can also get a free DID number, from "Area Code Earth", which is 883. Those numbers, also called INum, are an initiative from Voxbone, a Belgium company that also provide more services. Unfortunately those international networks are not always good accessible as some providers still lag behind. There is a work-around with a dial in number. For my country, the Netherlands, that is +31 208080808.

Besides getting called, you also want to call yourself. The company Voipbuster is free for telephone traffic in the United States, Canada, Puerto Rico and Guam. And for landline in Andorra, Australia, Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, France, Hong Kong, Hungary, Iceland, Ireland, Italy, Japan, Luxembourg, Malaysia, Netherlands, New Zealand, Norway, Portugal, Singapore, South Korea, Spain, Switzerland and Taiwan.

Calling to mobile phones will cost generally between 0.150 and 0.200, but there are some positive exceptions for example China, Hong Kong, Japan, Pakistan, Russia, Slovak Republic, Ukraine, Uzbekistan. But also negative once like Bulgaria, Italy, Macedonia, Netherlands, Portugal, Romania, Serbia And Montenegro, Slovenia, Spain, Sweden, Switzerland.

Companies and nerds can also build there own VOIP central. A Mini Central for on your Raspberry Pi or a more serious once on Astrisk.







Bulgaria (Landline) 0.025
Bulgaria (Mobile) 0.240
Moldova (Landline) 0.180
Moldova (Mobile) 0.150
Netherlands (Landline) FREE*
Netherlands (Mobile) 0.250
Romania (Landline) 0.090
Romania (Mobile) 0.220
Russian Federation (Landline) 0.022
Russian Federation (Mobile) 0.070
Russian Federation [moscow] (Landline) 0.010
Russian Federation [st Petersburg] (Landline) 0.005
Ukraine (Landline) 0.090
Ukraine (Mobile) 0.160

Other Mobile

Other Mobiles cost generally between 0.150  and 0.200, exceptions are Canada, China, Hong Kong, Japan, Pakistan, Slovak Republic, United States, Uzbekistan (on the positive direction)

More expensive still are Italy, Macedonia, Portugal, Serbia And Montenegro, Slovenia, Spain, Sweden, Switserland,

Andorra 0.150
Azerbaijan 0.190
Australia 0.150
Austria 0.200
Belarus 0.200
Belgium 0.200
Bosnia-herzegovina 0.250
Canada FREE*
China 0.010
Croatia 0.130
Czech Republic 0.160
Denmark 0.150
Egypt 0.160
Estonia 0.180
Finland 0.150
France 0.140
Germany 0.200
Greece 0.170
Hong Kong 0.007
Hungary 0.180
India 0.017
Indonesia 0.030
Italy 0.230
Japan 0.065
Kazakhstan 0.190
Lithuania 0.150
Luxembourg 0.180
Macedonia 0.220
Malta 0.180
Mauritius 0.130
Norway 0.160
Pakistan 0.080
Poland 0.190
Portugal 0.220
Serbia And Montenegro 0.240
Slovak Republic 0.070
Slovenia 0.220
Spain 0.210
Suriname 0.120
Sweden 0.220
Switzerland 0.310
Turkey 0.15
United Kingdom (others) 0.180
United States FREE*
Uzbekistan 0.060